Cylinder head cover for a cylinder head of an internal combustion engine
A cylinder head cover for a cylinder head of an internal combustion engine having a gasket element between the cylinder head and the cylinder head cover in which the gasket element includes a vacuum chamber which is open on at least one side and produces a seal between the cylinder head cover and the cylinder head when a vacuum is applied.
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The invention relates to a cylinder head cover for a cylinder head of an internal combustion engine with a gasket element between the cylinder head cover and cylinder head.
Known cylinder head covers are placed on the cylinder head of an internal combustion engine and affixed to the cylinder head with the aid of fastening screws. The fastening screws are usually guided through fastening eyes integrally molded on the cylinder head cover and are screwed to the cylinder head underneath in a loss-proof manner. For a tight seal, a gasket inserted into the supporting area between the cylinder head cover and the cylinder head is guided through the area of the fastening eyes on the cylinder head and is pressed in the fastening direction by the fastening screws. With this known approach, the tightness of the seal between the cylinder head cover and the cylinder head is ensured by pressing the gasket element in the direction of the fastening force created by the screws. The effective direction of the sealing force which is transmitted by the gasket element corresponds to the effective direction of the fastening force created by the fastening screws.
High restoring forces resulting from the pressure of the gasket element in the direction of the fastening force are transmitted from the compressed gasket element to the cylinder head cover and especially at higher temperatures may result in relaxation of the cylinder head cover, which is usually made of plastic. To prevent such relaxation, which can result in leakage, the contact pressure of the cylinder head cover against the cylinder head must be reduced, but this entails the risk that the seal tightness may be compromised.
This relaxation can be reduced by an increased number of fastening screws because this results in an approximately uniform surface pressure. Furthermore, an improved reinforcement of the cylinder head cover may also be achieved by additional ribs. However, both of these measures are associated with an increased weight of the cylinder head cover and additional manufacturing and/or assembly costs.
Furthermore, another factor to be taken into account is that the gasket is also subjected to sliding forces and shearing forces which cause additional stress on the gasket due to the different coefficients of longitudinal expansion of the plastic cylinder head cover and the cylinder head, which is usually made of aluminum.
SUMMARY OF THE INVENTIONIt is therefore an object of the invention to provide an improved cylinder head cover for a cylinder head of an internal combustion engine.
Another object of the invention is to provide a cylinder head cover which can be securely mounted on a cylinder head using simple measures.
A further object of the invention is to provide a cylinder head cover which ensures an adequate tight seal over a long service life.
These and other objects are achieved in accordance with the present invention by providing a cylinder head cover for a cylinder head of an internal combustion engine with a gasket element between the cylinder head cover and cylinder head, wherein the gasket element is associated with a sealing surface on the cylinder head or the cylinder head cover, and the gasket element comprises a vacuum chamber which is open on at least one side, the open side of the vacuum chamber facing the associated sealing surface on the cylinder head or cylinder head cover.
One advantage of the invention is that the gasket is constructed so that a vacuum supports the seal between the cylinder head and the cylinder head cover. Accordingly, a circumferential vacuum chamber is provided within the gasket element toward the side of the cylinder head or the cylinder head cover. As soon as a vacuum is applied, the gasket element is pulled against the respective component. This ensures a reliable seal. In an internal combustion engine, the vacuum may be generated by an external vacuum source. In automotive engineering, it is standard practice for a vacuum to be generated, provided and/or stored on the basis of the suction vacuum. This vacuum, which is available while the internal combustion engine is in operation, may be used for this sealing principle. If the internal combustion engine is not being operated and the vacuum declines, the vacuum in the vacuum chamber of the gasket element will also be reduced. In this case, however, contact between the cylinder head and cylinder head cover is still ensured, so this is not a disadvantage.
In accordance with to one embodiment, the gasket element comprises at least one lip-shaped profiled gasket for sealing the vacuum chamber. This sealing principle is extremely reliable and is also capable of compensating for minor unevenness.
In accordance with another embodiment of the invention, a fixation element is provided for securing the cylinder head cover on the cylinder head. If a vacuum is not available while the engine is shut down or is available only to a slight extent, the fixation element ensures reliable positioning of the cylinder head cover on the cylinder head. To accommodate the gasket element, a web is provided on the cylinder head or on the cylinder head cover, engaging at least partially in the vacuum chamber of the gasket element. By appropriately shaping the web and the vacuum chamber, it forms a loss-proof design, so the cylinder head cover can be assembled without any great complexity.
In accordance with yet another embodiment of the invention, the vacuum chamber is constructed so that the vacuum acts on both the cylinder head cover and the cylinder head. This eliminates a non-releasable fixation of the gasket element on one of the components. Fixation via the web described hereinafter, for example, is sufficient.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either alone or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention will be described in further detail hereinafter with reference to illustrative preferred embodiments shown in the accompanying drawing figures, in which:
The sealing concept according to
The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations within the scope of the appended claims and equivalents thereof.
Claims
1. A cylinder head cover for a cylinder head of an internal combustion engine with a gasket element between the cylinder head cover and cylinder head, wherein the gasket element is associated with a sealing surface on the cylinder head or the cylinder head cover, and the gasket element comprises a vacuum chamber which is open on at least one side, the open side of the vacuum chamber facing the associated sealing surface on the cylinder head or cylinder head cover.
2. A cylinder head cover according to claim 1, wherein the gasket element comprises at least one lip-shaped profile gasket for sealing the vacuum chamber of the gasket element to the associated sealing surface.
3. A cylinder head cover according to claim 1, wherein at least one fixation element is provided for fixing the cylinder head cover on the cylinder head.
4. A cylinder head cover according to claim 1, wherein the gasket element is mounted on one of the cylinder head and cylinder head cover; the associated sealing surface is on the other of the cylinder head and cylinder head cover, and the vacuum chamber is in contact with said sealing surface.
5. A cylinder head cover according to claim 1, wherein the cylinder head cover comprises a circumferential web which is received in a slot or groove in the gasket element.
6. A cylinder head cover according to claim 5, wherein the vacuum chamber of the gasket element is open toward the web as well as toward the sealing surface on the cylinder head, and the circumferential web engages at least partially in the vacuum chamber.
Type: Application
Filed: Jun 30, 2006
Publication Date: Jan 18, 2007
Applicant: Mann & Hummel GmbH (Ludwigsburg)
Inventor: Torsten Hilpert (Erdmannhausen)
Application Number: 11/477,766
International Classification: F01M 9/10 (20060101);